Search Results

Search found 5705 results on 229 pages for 'observer pattern'.

Page 39/229 | < Previous Page | 35 36 37 38 39 40 41 42 43 44 45 46  | Next Page >

• Decorator Pattern on List<T> for DataGridView

  - by elector

  Hi all, I would like to apply a Decorator on List class and be able to bind it to the WinForms DataGirdView. I would like to know what members of List i need to implement for this new class to be able to bind it to DataGrid. Some of the methods from List I would hide with my decorated class methods and others I would just call _decoratedList.Method(). Is this an option for implementing Decorator on List type? Decorator: public class MyCustomList : List<MyObject> { List<MyObject> _decoratedList; . . . }

  Read the article

• Create view or SP, only if the DB contains a pattern

  - by Randall Salas

  Hi all: I am working on a script, that needs to be run in many different SQL servers. Some of them, shared the same structure, in other words, they are identical, but the filegroups and the DB names are different. This is because is one per client. Anyway, I would like when running a script, If I chose the wrong DB, it should not be executed. I am trying to mantain a clean DB. here is my example, which only works for dropping a view if exists, but does not work for creating a new one. I also wonder how it would be for creating a stored procedure. Thx a lot. if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[ContentModDate]') and OBJECTPROPERTY(id, N'IsView') = 1) AND CHARINDEX('Content', DB_NAME()) 0 drop view [dbo].[ContentModDate] GO IF (CHARINDEX('Content', DB_NAME()) 0)BEGIN CREATE VIEW [dbo].[Rx_ContentModDate] AS SELECT 'Table1' AS TableName, MAX(ModDate) AS ModDate FROM Tabl1 WHERE ModDate IS NOT NULL UNION SELECT 'Table2', MAX(ModDate) AS ModDate FROM Table2 WHERE ModDate IS NOT NULL END END GO

  Read the article

• Events and references pattern

  - by serhio

  In a project I have the following relation between BO and GUI By e.g. G could represent a graphic with time lines, C a TimeLine curve, P - points of that curve and T the time that represents each point. Each GUI object is associated with the BO corresponding object. When T changes GUI P captures the Changed event and changes its location. So, when G should be modified, it modifies internally its objects and as result T changes, P moves and the GuiG visually changes, everything is OK. But there is an inconvenient of this architecture... BO should not be recreated, because this will breack the link between BO and GUIO. In particular, GUI P should always have the same reference of T. If in a business logic I do by e.g. P1.T = new T(this.T + 10) GUI_P1 will not move anymore, because it wait an event from the reference of former P1.T object, that does not belongs to P1 anymore. So the solution was to always modify the existing objects, not to recreate it. But here is an other inconvenient: performance. Say I have a ready newC object that should replace the older one. Instead of doing G1.C = newC I should do foreach T in foreach P in C replace with T from P from newC. Is there an other more optimal way to do it?

  Read the article

• Mixing Transaction Script pattern with DDD/CQRS

  - by Herman

  Hi all, Here is the situation, in order to support our legacy system, we need to insert to a table whenever a user logs in. This is basically an CRUD operation, so it doesn't really make sense to create repository/entity/command/event for this since this doesn't tie to any business rules at all. The only benefit to create a CQRS command is that this database write can happen asynchronously under that model. Which is a better route to take? Use CQRS, and then call a stored proc. when handling that command? Just call database directly in the controller (I am using asp.net mvc)

  Read the article

• Pattern for null settings

  - by user21243

  Hi, I would like to hear your thoughts and ideas about this one. in my application i have controls that are binded to objects properties. but.. the controls always looks like that: a check box, label that explain the settings and then the edited control (for ex: text box) when unchecking the checkbox i disable the text box (using binding) when the checkbox is unchecked i want the property to contain null, and when it is checked i would like the property to contain the text box's text. Of course text box can be NumericUpDown, ComboBox, DatePicker etc.. Do you have any smart way of doing it using binding or do i have to do everything on code; I really would like to a build a control that supports that and re-use it all over Ideas? Thanks,

  Read the article

• Pattern Matching in Columns

  - by Chronicles

  File 1 A11;F1;BMW A23;F2;BMW B12;F3;BMW H11;F4;JBW File 2 P01;A1;0;0--00 ;123;456;150 P01;A11;0;0--00 ;123;444;208 P01;B12;0;0--00 ;123;111;36 P01;V11;0;0--00 ;123;787;33.9 Output -;-;-;P01;A1;0;0--00 ;123;456;150 A11;F1;BMW;P01;A11;0;0--00 ;123;444;208 B12;F3;BMW;P01;B12;0;0--00 ;123;111;36 -;-;-;P01;V11;0;0--00 ;123;787;33.9 I TRIED awk 'FNR==NR {a[$2] = $0; next }{ if($1 in a) {p=$1;$1="";print a[p],$0}}' File1 File2 But didnt work. Basically I want to get the details from FILE 1 and compare with FILE2 (master list) . Example : A1 in FILE2 was not available in FILE1 , so in output file we have “-“ for 1st three fields and rest from FILE2 . Now, we have A11 and we got the detail in FILE1. So we write details of A11 from both File 1 & 2

  Read the article

• How to perform duplicate key validation using entlib (or DataAnnotations), MVC, and Repository pattern

  - by olivehour

  I have a set of ASP.NET 4 projects that culminate in an MVC (3 RC2) app. The solution uses Unity and EntLib Validation for cross-cutting dependency injection and validation. Both are working great for injecting repository and service layer implementations. However, I can't figure out how to do duplicate key validation. For example, when a user registers, we want to make sure they don't pick a UserID that someone else is already using. For this type of validation, the validating object must have a repository reference... or some other way to get an IQueryable / IEnumerable reference to check against other rows already in the DB. What I have is a UserMetadata class that has all of the property setters and getters for a user, along with all of the appropriate DataAnnotations and EntLib Validation attributes. There is also a UserEntity class implemented using EF4 POCO Entity Generator templates. The UserEntity depends on UserMetadata, because it has a MetadataTypeAttribute. I also have a UserViewModel class that has the same exact MetadataType attribute. This way, I can apply the same validation rules, via attributes, to both the entity and viewmodel. There are no concrete references to the Repository classes whatsoever. All repositories are injected using Unity. There is also a service layer that gets dependency injection. In the MVC project, service layer implementation classes are injected into the Controller classes (the controller classes only contain service layer interface references). Unity then injects the Repository implementations into the service layer classes (service classes also only contain interface references). I've experimented with the DataAnnotations CustomValidationAttribute in the metadata class. The problem with this is the validation method must be static, and the method cannot instantiate a repository implementation directly. My repository interface is IRepository, and I have only one single repository implementation class defined as EntityRepository for all domain objects. To instantiate a repository explicitly I would need to say new EntityRepository(), which would result in a circular dependency graph: UserMetadata [depends on] DuplicateUserIDValidator [depends on] UserEntity [depends on] UserMetadata. I've also tried creating a custom EntLib Validator along with a custom validation attribute. Here I don't have the same problem with a static method. I think I could get this to work if I could just figure out how to make Unity inject my EntityRepository into the validator class... which I can't. Right now, all of the validation code is in my Metadata class library, since that's where the custom validation attribute would go. Any ideas on how to perform validations that need to check against the current repository state? Can Unity be used to inject a dependency into a lower-layer class library?

  Read the article

• multiple classes with same methods - best pattern

  - by Tony

  I have a few classes in my current project where validation of Email/Website addresses is necessary. The methods to do that are all the same. I wondered what's the best way to implement this, so I don't need to have these methods copy pasted everywhere? The classes themselves are not necessarily related, they only have those validation methods in common.

  Read the article

• How to get everything in the string, but a particular pattern

  - by José Leal

  Yet another regexp question: I have a string as the following, "This is a string, and I have a priority !1" So I want to build a regexp that extracts my priority, which is this number 1 preceded by the "!". To extract it is very easy, "!([1-4])". But now I want to extract the text, leaving it out! How can I do that? DETAIL: The !1 can be anywhere in the string, so this is also perfectly fine: "This is a string, !1 and I have a priority" Thanks! UPDATE: I'm using scala

  Read the article

• parse part of the text from regex pattern

  - by dalco

  I have a string: [\n['-','some text what\rcontains\nnewlines'],\n\n trying to parse: Regex.Split(@"[\n['-','some text what contains newlines'],\n\n", @"\[\n\['(.*)','(.*)'],.*"); but the split return array seems to be null i need to get part of text: "some text what contains newlines"

  Read the article

• Is there a pattern for initializing objects created wth a DI container

  - by Igor Zevaka

  I am trying to get Unity to manage the creation of my objects and I want to have some initialization parameters that are not known until run-time: At the moment the only way I could think of the way to do it is to have an Init method on the interface. interface IMyIntf { void Initialize(string runTimeParam); string RunTimeParam { get; } } Then to use it (in Unity) I would do this: var IMyIntf = unityContainer.Resolve<IMyIntf>(); IMyIntf.Initialize("somevalue"); In this scenario runTimeParam param is determined at run-time based on user input. The trivial case here simply returns the value of runTimeParam but in reality the parameter will be something like file name and initialize method will do something with the file. This creates a number of issues, namely that the Initialize method is available on the interface and can be called multiple times. Setting a flag in the implementation and throwing exception on repeated call to Initialize seems way clunky. At the point where I resolve my interface I don't want to know anything about the implementation of IMyIntf. What I do want, though, is the knowledge that this interface needs certain one time initialization parameters. Is there a way to somehow annotate(attributes?) the interface with this information and pass those to framework when the object is created? Edit: Described the interface a bit more.

  Read the article

• Regex to match 4 repeated letters in string using java pattern

  - by Anonymous user

  i want to match something like aaaa, aaaad, adjjjjk. Something like this ([a-z])\1+ was used to match the repeated characters but i am not able to figure this out for 4 letters.

  Read the article

• C#: Preferred pattern for functions requiring arguments that implement two interfaces

  - by JS Bangs

  The argument to my function f() must implement two different interfaces that are not related to each other by inheritance, IFoo and IBar. I know of two different ways of doing this. The first is to declare an empty interface that inherits from both: public interface IFooBar : IFoo, IBar { // nothing to see here } public int f(IFooBar arg) { // etc. } This, of course, requires that the classes declare themselves as implementing IFooBar rather than IFoo and IBar separately. The second way is to make f() generic with a constraint: public int f<T>(T arg) where T : IFoo, IBar { // etc. } Which of these do you prefer, and why? Are there any non-obvious advantages or disadvantages to each?

  Read the article

• How can I avoid a specific string pattern from being replaced by Regex.replace ()

  - by Taz

  I have a string like Pakistan, officially the <a href="Page.aspx?Link=Islamic Republic of Pakistan">Islamic Republic of Pakistan</a> Now I am using System.Text.RegularExpressions.Regex.Replace(inputText, "(\\bPakistan\\b)", "something"); to replace Pakistan outside the tags. But I don't want to replace Pakistan occurring within the <a></a> tags.

  Read the article

• Framework or design pattern for mailing all users of a webapp

  - by Todd Owen

  My app takes care of user registration (with the option to receive email announcements), and can easily handle the actual template-based rendering of email for a given user. JavaMail provides the mail transport layer. But how should I design the application layer between the business objects (e.g. User) and the mail transport? The straightforward approach would be a simple, synchronous loop: iterate through the users, queue the emails, and be done with it. "Queue" might mean sending them straight to the MTA (mail server), or to an in-memory queue to be consumed by another thread. However, I also plan to implement features like throttling the rate of emails, processing bounced emails (NDRs), and maintaining status across application restarts. My intuition is that a good design would decouple this from both the business layer and the mail transport layer as much as possible. I wondered if others had solved this problem before, but after much searching I haven't found any Java libraries which seem to fit this problem. Standalone mail apps such as James or list servers are too large in scope; packages like Spring's MailSender or Commons Email are too small in scope (being basically drop-in replacements for JavaMail). For other languages I haven't found anything appropriate either. I'm curious about how other developers have gone about adding bulk mailing to their applications.

  Read the article

• Canonical pattern reference in Actors programming model.

  - by Bubba88

  Hello! Is there a source, which I could use to learn some of the most used and popular practices regarding Actor-/Agent-oriented programming. My primary concern is about parallelism and distribution limited to the mentioned scheme - Actors, message passing. Should I begin with Erlang documentation or maybe there is any kind of book that describes the most important building blocks when programming Actor-oriented? Thank you! (Most useful examples would be in Scala or F#)

  Read the article

• Haskell: Pattern Matching with Lists

  - by user1670032

  I'm trying to make a function that takes in a list, and if one of the elements is negative, then any elements in that list that are equal to its positive counterpart should be changed to 0. Eg, if there is a -2 in a list, then all 2's in that list should be changed to 0. Any ideas why it only works for some cases and not others? I'm not understanding why this is, I've looked it over several times. changeToZero [] = [] changeToZero [x] = [x] changeToZero (x:zs:y:ws) | (x < 0) && ((-1)*(x) == y) = x : zs : 0 : changeToZero ws changeToZero (x:xs) = x : changeToZero xs *Main changeToZero [-1,1,-2,2,-3,3] [-1,1,-2,2,-3,3] *Main changeToZero [-2,1,2,3] [-2,1,0,3] *Main changeToZero [-2,1,2,3,2] [-2,1,0,3,2] *Main changeToZero [1,-2,2,2,1] [1,-2,2,0,1]

  Read the article

• Trouble implementing Singleton pattern in Tomcat web application due to Class Loader

  - by jwegan

  I'm trying to implement a Singleton in Tomcat 6.24 on Linux with x86_64 OpenJDK 1.6. My application is just a bunch of JSPs and some static content and the JSPs make calls to my Java code. Currently the web.xml just looks like this: <web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5"> <description> App Name </description> <display-name>App Name</display-name> <!-- The Usual Welcome File List --> <welcome-file-list> <welcome-file>pages/index.jsp</welcome-file> </welcome-file-list> </web-app> Before when I was trying to load my Singleton it was getting instantiated twice since the class was getting loaded by two different class loaders (I'm not sure why) and each loader would create an instance of the singleton which is not acceptable for my application. I finally figured out if I exported my code as a jar and put it in $CATALINA_HOME/lib then there was only one instance, but this is not an elegant solution. I've been googling for hours, but I haven't come up with anything yet. I'm wondering if there is some other solution. Currently I'm not precompling my JSPs, could this be part of the problem? Could I write a servlet to ensure the singleton is created? If so how do I do that?

  Read the article

• Can't declare unused exception variable when using catch-all pattern

  - by b0x0rz

  what is a best practice in cases such as this one: try { // do something } catch (SpecificException ex) { Response.Redirect("~/InformUserAboutAn/InternalException/"); } the warning i get is that ex is never used. however all i need here is to inform the user, so i don't have a need for it. do i just do: try { // do something } catch { Response.Redirect("~/InformUserAboutAn/InternalException/"); } somehow i don't like that, seems strange!!? any tips? best practices? what would be the way to handle this. thnx

  Read the article

• Count subset of binary pattern ..

  - by mr.bio

  Hi there . I have a A=set of strings and a B=seperate string. I want to count the number of occurences in from B in A. Example : A: 10001 10011 11000 10010 10101 B: 10001 result would be 3.(10001 is a subset of 10001,10011,10101) So i need a function that takes a set and string and returns an int. int myfunc(set<string> , string){ int result; // My Brain is melting return result ; }

  Read the article

• design pattern tools to use?

  - by ajsie

  i have noticed that every area has some tools you can use to make things easier. eg. css = dreamweaver doctrine/propel = orm designer // you dont have to hardcore code schemas manually and remembering all the syntax/variables mysql = mysql workbench // the same etc. in this way you get aided and dont have to type things the hard way, and can learn the structure, but then use GUI tools to help you develop faster. now i'm learning design patterns (singleton, factory, command, memento etc) and im wondering if there are some kind of tools you can use that will help you develop faster. i dont know exactly what tools i'm trying to find, just helping me when coding with design patterns (schema drawings? references?) are there any?

  Read the article

• Choosing a design pattern for a class that might change it's internal attributes

  - by the_drow

  I have a class that holds arbitrary state and it's defined like this: class AbstractFoo { }; template <class StatePolicy> class Foo : public StatePolicy, public AbstractFoo { }; The state policy contains only protected attributes that represent the state. The state might be the same for multiple behaviors and they can be replaced at runtime. All Foo objects have the same interface to abstract the state itself and to enable storing Foo objects in containers. I would like to find the least verbose and the most maintainable way to express this.

  Read the article

• wpf command pattern

  - by evan

  I have a wpf gui which displays a list of information in separate window and in a separate thread from the main application. As the user performs actions in the main window the side window is updated. (For example if you clicked page down in the main window a listbox in the side window would page down). Right now the architecture for this application feels very messy and I'm sure there is a cleaner way to do it. It looks like this: Main Window contains a singleton SideWindowControl which communicates with an instance of the SideWindowDisplay using events - so, for example, the pagedown button would work like: 1) the event handler of the button on the main window calls SideWindowControl.PageDown() 2) in the PageDown() function a event is created and thrown. 3) finally the gui, ShowSideWindowDisplay is subscribing to the SideWindowControl.Actions event handles the event and actually scrolls the listbox down - note because it is in a different thread it has to do that by running the command via Dispatcher.Invoke() This just seems like a very messy way to this and there must be a clearer way (The only part that can't change is that the main window and the side window must be on different threads). Perhaps using WPF commands? I'd really appreciate any suggestions!! Thanks

  Read the article

• Override Maven's default resource filter replacement pattern.

  - by Matt Campbell

  By default maven will filter resources like this: <properties> <replace.me>value</replace.me> </properties> <some-tag> <key>${replace.me}</key> </some-tag> will get you: <some-tag> <key>value</key> </some-tag> Is there a way to override the way maven selects the strings to replace? Specifically, I want to be able to use this: <some-tag> <key>@replace.me@</key> </some-tag> to get the same result as above.

  Read the article

• Client-server synchronization pattern / algorithm?

  - by tm_lv

  I have a feeling that there must be client-server synchronization patterns out there. But i totally failed to google up one. Situation is quite simple - server is the central node, that multiple clients connect to and manipulate same data. Data can be split in atoms, in case of conflict, whatever is on server, has priority (to avoid getting user into conflict solving). Partial synchronization is preferred due to potentially large amounts of data. Are there any patterns / good practices for such situation, or if you don't know of any - what would be your approach? Below is how i now think to solve it: Parallel to data, a modification journal will be held, having all transactions timestamped. When client connects, it receives all changes since last check, in consolidated form (server goes through lists and removes additions that are followed by deletions, merges updates for each atom, etc.). Et voila, we are up to date. Alternative would be keeping modification date for each record, and instead of performing data deletes, just mark them as deleted. Any thoughts?

  Read the article

< Previous Page | 35 36 37 38 39 40 41 42 43 44 45 46  | Next Page >